Thomson acquired from Silver Mines Limited (ASX: SVL) the Webbs and Conrad silver projects, covering approximately 86km2, in the New England Fold Belt, NSW.
Webbs Silver Project
The Webbs Silver Project is a very high-grade silver bearing lode system located in northern New South Wales (see Figure 1). Webbs is considered one of the highest-grade undeveloped silver projects in Australia.
Silver mineralisation at Webb’s was discovered in 1884. From 1884 to 1901 approximately 55,000t of ore was mined at an average grade of at least 23oz/t silver. At Webb’s Main, mining reached 210m below surface and extracted a high grade south plunging chute. Numerous shafts some up to 50m deep and smaller prospecting pits occur along the 2km long trend.
Location and Geology
The Webbs Deposit is located approximately 65 kilometres northeast of Inverell and 230 kilometres southwest of the Gold Coast in northern New South Wales, Australia. The area consists of moderate to steep wooded hills, open farm country and open country and is dissected by several seasonal streams.
EL5674 comprises 4 graticular units for Group One Minerals and is cantered about 10km north of Emmaville, in northern New South Wales. The license is located within the New England Fold Belt (Figure 2) which comprises Palaeozoic meta-sediments and volcanics, intruded by granites and granodiorites.
The dominant feature in the area is the Upper Permian Mole Granite., part of the large New England Batholith that extends over more than 400 km along the east coast of Australia. The batholith formed between 270 Ma and 225 Ma along an Andean-type active continental margin and consists of a large number of individual plutons that intruded in several pulses into a complex crustal association of the New England Fold Belt, now recognised as an orogenic wedge sequence.
Three lines of lode are identified in the vicinity of the main shaft, with historical production mainly from the Central lode. Two lodes, identified as ‘Eastern’ and ‘Western’ lodes, form a left hand en-echelon arrangement and are potentially structurally repeated equivalents of the Central lode.There are several down-plunge extensions that require testing by drilling and the remainder of the tenement is largely underexplored.
Conrad Silver Project
The Conrad Mine and deposit represents a polymetallic exploration and mining opportunity located in northern New South Wales.
The Conrad mine was previously one of the largest silver producing mines in the New England region, with about 3.5 million ounces of silver production recorded from around 175,000 tonnes of ore, together with by-product lead, zinc, copper and tin. Recorded average grades were of the order of 600g/t Ag, 8% Pb, 4% Zn, 1.5% Cu and 1.5% Sn. The lodes were worked over a 1.4km strike length to a maximum depth of 267m.
Production commenced in 1891 and continued until 1912, when production ceased. Mining-related activities re-commenced in 1947 when Brocken Hill South acquired the property, and further production took place from 1955 to 1957.
Prior to being acquired by Silver Mines in 2015/16, the project was explored by Malachite Resources NL. Over 25,000 metres of predominantly diamond drilling has been completed in the modern era exploration. Drilling has focused on the King Conrad, Conrad and Greisen Zones, with very little exploration drilling outside of the main line of lodes.
Previous exploration at Conrad has predominantly focused on the main Conrad line of lode, with a number of mineral occurrences within the permits underexplored.
Location and Geology
The Conrad deposit lies in the southern New England Fold Belt and is hosted in batholiths belonging to the Permo-Triassic Moonbi Super-suite. The Tingha Adamellite and the Gilgai Granite, underlie the entire Conrad project area and host the Conrad Lode System. These rocks form a roughly circular, composite pluton of about 70km in diameter. The Gilgai Granite, which is interpreted to have intruded the Tingha Adamellite, is the main unit of interest as it is a highly mineralised, fractionated I-type granitoid.
The Conrad deposit comprises the Conrad Lode, the King Conrad Lode and the Greisen Zone; text references to a Davis Lode relate to a SE extension of the Conrad Lode. The Conrad/King Conrad Lode has approximately 2.3km of strike length in a north-west direction. The lode occurs at the NW end of a fault zone that has 7.5km of strike, and which transects the Tingha Adamellite and Gilgai Granite on the western side of the pluton. At the northwest end of the Conrad Lode is a zone of broad, more intense alteration known as the Greisen Zone, which locally outcrops.